Abstract: In this paper, calcium lactate was made from eggshell. The eggshell was properly shattered, the lactate was added in to react with eggshell to prepare calcium lactate by direct reaction. The factors in the reaction were studied, and the optimal reaction condition was obtained. The results of regression-orthogonal combination experiment were analyzed by significance analysis. The results showed that the optimum conditions were: adding eggshell powder 10 g, lactic acid 18.5 mL, distilled water 100 mL, and the reaction temperature 35℃, reaction time 2 h, the yield of calcium lactate can reach 79.23% and the content is 86.93% in the optimal condition. Preparation calcium lactate in this way could not only utilize the potential of the eggshell but also solve the environmental pollution problem caused by the eggshell.